PCB Substrate with Transition Metal Adhesion Layer
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Solution Overview
Problem
Traditional substrates for printed circuit boards require expensive vacuum equipment for metal layer formation, limiting size and increasing costs, and struggle to achieve high peel strength and thin metal layers for high-density applications.
Innovation Solution
A substrate with a base film containing a transition metal from group 10, such as nickel or palladium, where the metal layer is formed using conductive ink and non-electrolytic plating, eliminating the need for vacuum equipment and enhancing adhesion without an adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sputtering method is used to form the metal layer in close contact with the base film, then the peel strength between the metal layer and base film is improved, but the cost of construction, maintenance, and operation of vacuum equipment increases
Solution Approach 1:
The invention extracts and eliminates the vacuum equipment requirement from the metal layer formation process. By using a conductive ink formulation that can be applied via conventional coating methods (such as screen printing, spray coating, or dip coating) and then sintered to form a conductive metal layer, the process removes the need for expensive vacuum sputtering equipment while achieving sufficient adhesion between the metal layer and base film through chemical bonding mechanisms in the ink composition.
Solution Approach 2:
The invention replaces the mechanical/physical vapor deposition process (sputtering) with a chemical-based solution process. The conductive ink contains metal particles suspended in a vehicle that, when applied and sintered, forms a conductive layer through chemical bonding and particle sintering rather than physical vapor deposition, thereby substituting complex mechanical vacuum equipment with simpler thermal processing equipment.
2Strength
If a sputtering method is used to form the metal layer, then the metal layer can be formed in close contact with the base film, but the size of the substrate is limited by equipment constraints
Solution Approach 1:
The invention extracts the substrate size limitation imposed by vacuum chamber dimensions. By using a solution-based conductive ink that can be applied through conventional coating techniques (screen printing, spray coating, dip coating), the process enables formation of conductive layers on large-area substrates that exceed the capacity of vacuum sputtering equipment, while maintaining adequate contact quality through the ink's adhesion promoters and sintering process.
3Quantity of substance
If a thin copper layer is used to meet high-density requirements, then the printed circuit board density is improved, but the peel strength between the metal layer and base film decreases
Solution Approach 1:
The invention uses a composite conductive ink formulation containing metal particles (such as copper, silver, or nickel), adhesion promoters, and binding agents. This composite structure allows the formation of thin conductive layers with enhanced interfacial bonding to the base film. The adhesion promoters and binding agents in the ink create strong chemical bonds between the thin metal layer and the substrate, compensating for the reduced thickness and maintaining high peel strength even at thicknesses suitable for high-density applications.
Solution Approach 2:
The invention changes the material composition parameters of the conductive layer by using a formulated ink rather than pure metal deposition. The ink contains controlled ratios of metal particles, adhesion promoters, and binders that, when sintered, create a thin layer with optimized balance between conductivity and adhesion. This parameter adjustment allows thin layers to achieve peel strengths comparable to or exceeding traditional thicker sputtered layers.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a low-cost, thin metal layer with high peel strength, enabling the production of high-density printed circuit boards without the limitations of vacuum equipment, ensuring strong adhesion and reduced residual stresses.
Implementation Method 1
forming a first conductive layer by applying a conductive ink containing metal particles to at least one surface of a base film having insulating properties and heating the conductive ink
Implementation Method 2
dispersing the transition metal in group 10 into the base film
Implementation Method 3
forming a second conductive layer on a surface of the first conductive layer opposite a surface on which the base film lies by non-electrolytic plating with a plating solution containing a transition metal in group 10 of the periodic table
Data Source
AI summary
The substrate for a printed circuit board according to an embodiment of the present invention includes a base film having insulating properties, and a metal layer stacked on at least one surface of the base film, in which the base film includes a portion where a transition metal in group 10 of the periodic table is present. The transition metal in group 10 is preferably nickel or palladium. The portion where the transition metal in group 10 is present preferably includes a region having an average thickness of 500 nm and extending from an interface with the metal layer.